Volume 53, Whakatane, 1991

An evaluation of agroforestry on a Bay of Plenty hill country farmR.L. KNOWLES, G.M. BRANN and G.J. BRANN

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Between 1970 and 1991,53 ha of Pinus radiata
plantations were established and managed in an
agroforestry system on a 245 ha farm at Roydon
Downs in the eastern Bay of Plenty. Plantations on
a further 30 haareplanned. This paperoutlines the
experience gained, and uses recently developed
agroforestry modelling systems to evaluate the
current and projected physical yields, cash flow
and profitability of several agroforestry options
when applied to a typical Bay of Plenty sheep and
beef farm, The increasing availability of genetically
improved tree stocks, together with developments
in silvicultural techniques, have resulted in a low
cost, easily managed tree crop, using mainly
family labour. The objective is to produce high
quality domestic or export sawlogs and peeler
logs. Planting the least productive third of the
farm is predicted to more than double the total
farm surplus. For farming to provide an equivalent
economic return from the same land, gross margins
would have to increase from $29 to $60/livestock
unit (LSU). or livestock carrying capacity would
have to increase from 8 to 16 LSU/ha. Options
involving 135 stems/ha and 225 stems/ha gave a
similar economic return. However, concerns about
the quality of the final product indicate that cash
flow constraints should be met by varying the size
and rate of planting, rather than by reducing final
crop stocking. A method of financing initial costs
based on sharing final revenues with investors is
presented.
Keywords agroforestry, Pinus radiata, estate
model, profitability

Analysis of 10 years’ production data within a discussion group. What factors
are limiting production?ANDRE HICKSON

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An analysis of 10 years’ production records of a
group of farms indicated that for all the improved
management techniques employed, production had
not increased. Kilograms of milkfat per hectare did
notgiveameasureofresourceuseorthemanagement
ability of the farmer.
Farmers were surveyed. The following data were
collected for the years 1978/79 to 1987/88:
Keywords index, management performance, goal,
objective.

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Facial eczema (FE) is a disease of grazing ruminants
caused by ingesting spores of the fungus Pithomyces
chartarum. The spores contain a toxic compound,
sporidesmin, which causes liver injury, sensitivity
to sunlight and reduced performance in susceptible
dairy cattle. The extent of production losses is
summarised. Research at Ruakura has demonstrated
that the resistance of animals to FE is inherited,
with a heritability estimate of 0.31 in dairy cattle.
Genetic progress in dairy cattle could bc achieved by
progeny testing young bulls, and selecting for
use as sires those with the most resistant progeny.
However, work over the last decade in sheep at
Ruakura has demonstrated the success of selection
based on performance testing (i.e. dosing potential
sires themselves and using those that are most
resistant to the challenge). In January 1990 we
began to develop a performance test for use in the
preliminary screening of young dairy bulls for FE
resistance. The details of these tests are described.
Keywords facial eczema, dairy cattle, performance testing, production loss

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Recent results from field trials comparing the
agronomic effectiveness of water soluble fertilisers
(single superphosphate (SSP), triple superphosphate
(TSP)) and fertilisers of low water
solubility (‘slow release’, reactivephosphaterock
(RPR) fertilisers) are reviewed.
It is shown that the pasture production data
from the ‘National Series’ of trials are consistent
with, and can be described by, a model for the
dissolution of RPR in soil. Applying both the
pasture production data and the dissolution model
the term ‘lag time’ associated with ‘slow release’
RPR is defined and quantified for New Zealand
conditions.
Results show that on average the rate of release
of P from RPR is about 30% within the year of
application, 23% in year 2 and progressively less in
subsequent years. It follows that when RPR is
applied annually, the amount of Preleased annually,
from the current application and from the residues
of previous annual applications, is 30,53,70,82,
9 1,96% as a fraction of the total P applied annually.
Consequently about 3.5 times the amount of RPRP
is required to achieve the same yield as soluble P
in year 1, about 2 times in year 2 and 1.5 in year 3.
The lag time is defined as the time required to
accumulate sufficient RPR residues in the soil
from applications such that the annual amount of
P dissolved from RPR each year is equal to or
greater than 90% of the amount of total RPR-P
applied annually. The lag time associated with
RPR use is about 4-6 years depending on the site.
The agronomic performance of RPR based on
the National Series data was not associated with
soil pH (5.1 to 6.3), annual rainfall (700 to 1800
mm) or soil phosphate retention (13-98%). This probably reflects the narrow range and confounding
effects of the soil and climate factors. The
experimental basis for the current soil pH and
rainfall boundary conditions are briefly discussed.
Available evidence suggests that the P dissolved
from RPR has the same agronomic effectiveness
as P from soluble fertiliscrs.
The agronomic implications of these results on
P fertilisers of intermediate solubility (i.e. PAPR
and Longlife) are discussed in relation to field
results.
Keywords agronomy, comparison, dissolution,
fertilisers, Longlife, PAPR,phosphorus, RPR, slow
release, soluble P, single superphosphate, triple
superphosphate

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This paper compares a herbal ley (of particular
interest to farmers involved in the ‘organic’ branch
of agriculture) with a conventional pasture
(ryegrass-white clover) and a more intensive
system (pure ryegrass receiving 400 kg fertiliser
N/ha/yr) in a study lasting 2 years. The herbal ley
seeds mixture was prepared following the
pioneering ideas of Robert Elliot in his “Clifton
~~ ~~~~~Park”mixture,-whichbasically-included~a-group
of ‘non-aggressive’ grasses, forage legumes and
herbs. Pasture production (average of 2 years) from
Herbal ley was 15 t DM/ha/yr, representing
approximately 90% of the yield from the intensively
managed pure ryegrass pasture receiving 400 kg N/
ha&r and some 2530% more than from ryegrassclover.
A major feature of the herbal ley was
substantialproductionduringlate.springandsummer,
when chicory (the most dominant herb), and red
clover and white clover made a major contribution
to herbage yield. In winter the total yield was similar
tothatI?omthegrass-cloverpasture.L.egumecontent
was 23 and 3 1% (averaged over the year) for Grassclover
and Herbal ley pastures respectively. In spite
of this difference, symbiotic N fixation was similar.
So fixation efficiency on a legume yield basis was
50.3 and 3 1.6 kg N fixed/t legume DM harvested,
respectively. These results could reflect a different
pattern of utilisation of soil N, as a consequence of
the different botanical composition of the swards.
In summary, the performance of the herbal ley
offers the promise of an alternative, ‘specialist’
pasture and would be highly beneficial if quality
feed is required in summer.
Keywords herbal ley, biological fertility, nitrogen,
symbiotic nitrogen fixation, pasture mixtures

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Establishment of grasses and legumes drilled in
spring with a prototype strip seeder drill or a
conventional tripledisc drill werecomparedon two
sites in the presence and absence of paraquat. On
theE%rnscleughsite,plantestablishmentinautumn,
as a percentage of viable seed sown, was higher
with the prototype drill than with the triple disc drill
in the absence of paraquat. The application of
paraquat increased establishment with the triple
disc drill and differences between the drills were
not consistent over species. Paraquat had no
discernible effect on the competing vegetation or
establishment at Ohau Downs. Establishment of
birdsfoot trefoil, cocksfoot and tall fescue, but not
alsike clover, was significantly higher in autumn in
the prototype drill treatment. Treatment effects on
standing herbage mass on both sites followed a
similar trend to establishment although paraquat
increased herbage mass in the prototype drill
treatments on Eamscleugh, in contrast to the nonsignificant
effect on establishment. The present
results indicate the potential of the prototype strip
seeder drill for cost effective establishment of
improved pasture species in difficult environments.
Keywords direct drilling, establishment, strip
seeder, luceme, tall fescue, birdsfoot trefoil, upland
brome,alsike clover,cocksfoot,paraquat, herbicide

Dynamics of mineral nitrogen in topsoil, during regrowth of pasture in two
contrasting grassland systemsB.E. RUZ-JEREZ, P. ROGER BALL and R.E. WHITE

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Changes in soil mineral nitrogen(N) were monitored
during regrowth of pasture between consecutive
grazings in two contrasting grassland systems;
Grass-clover (the norm in NZ) and a more intensive
system, Grass+N400 (pure grass + 400 kg fertiliser
N/ha/year). The experiment was carried out during
autumn at DSIR Grasslands.Palmerston North. Net
mineralisation of N under field conditions was
estimate_d- i~n- an ancillary experiment, using soil
samples from undisturbed soil cores contained in
PVC tubes. The dynamics of mineral N in soil were
dominated by a ‘pulse’ of ammonium, observable
soon after grazing. Nitrification proceeded rapidly
thereafter. Mineral N in soil then progressively
declined, much of it going into organic combination
presumably through uptake by plants. Since nitrate
formation in the soil is minimised by maximising
the residence time of N in plant (organic) form,
differentmanagementoptions(varyinginfrequency
and intensity of defoliation) may have important
influences, not only on pasture utilisation and
production, but also on the management of mineral
N in the soil-plant-animal complex. Tubes
embedded in soil and incubated in the field have
provided some additional, useful perspectives.
There was only limitedevidence for significant net
mineralisation of organic N throughout the period
of regrowth. Analyses of individual soil cores
demonstrated a sharp contrast between the pasture
at large and the 10 - 15% of total area influenced by
urine from the previous grazing, in terms of mineral
N content. ‘Averaging’ these by bulking numerous
cores into a composite sample can provide an
accurate quantitative estimate of mineral N, which
can be related to herbage uptake of N over the
whole area. But if losses of N (by leaching or
volatilisation) are disproportionate to the
concentration of mineral N in affected and
unaffected volumes of soil, then bulking samples
and averaging will not be the most appropriate way
to estimate these losses. The results of this study point to the importance of the urine of grazing
ruminants as a N substrate for pasture regrowth in
the absence of fertiliser N. At the same time, urine
patches provide the main avenue for Nescape to the
wider environment from developed pastures.
Keywords mineral N, N in pastures, N cycling by
animals

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Plugs of sheep-grazed, ryegrass-dominant pasture
were transplanted to a glasshouse, in order to make
detailed studies of tiller appearance from the base
of flowering tillers in late spring-early summer. In
2 experiments, cutting treatments which reduced
the opportunity for transport of assimilate from
parent flowering tillers to daughter tillers markedly
reduced both numbers of daughter tillers formed
and their size. In one of the studies, proportion of
radioactive carbon dioxide fed to flowering tillers,
but recovered from daughter tillers, was 7.0%, and
this transported radiocarbon appeared to be
delivered preferentially to leaf elongation zones of
young tillers. There appear to be fundamental
differences in tillerbehaviour between ‘Grasslands
Ruanui’ ryegrass and ‘Ellett’ ryegrass. The
implications for farm practice are briefly discussed.
Keywords ryegrass, tiller dynamics, radiocarbon,
summer pasture production, pasture persistence

Effect of grazing management on minimising effects of parasitic nematodes
on lamb productionN.A. THOMSON and M.T. POWER

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An integrated management system involving cattle,
ewes and lambs developed to minimise levels
of parasitic nematode contamination of pasture
was evaluated in a 2-year (1989-1991) study. Four
experimental farmlets were managed as self-containcd
units over a May-May year. Over the two
years, stocking rate averaged 15 su/ha and
cattle:sheep ratio 35:65. Three treatments (lambs
regularly drenched, ewes drenched post-lambing/
lambs undrenchedand undrenchedewes andlambs)
were similarly managed (set-stocked, lambing to
weaning, 7-day shifts post-weaning, a 77-day interval
between consecutive lamb grazings and a strict
rotation of lambs followed by ewes with cattle midway
between the ewe and subsequent lamb grazing).
A fourth treatment differed in each year: in
year 1, lambs were set stocked over summer and in
year 2 cattle followed lambs, and ewes were positioned
mid-way in the rotation between lambs and
cattle,
In both years, the management system developed
to minimise nematode parasitism in lambs
mamtained low levels of infective larvae on pasture
(~80 L3 larvae/kg pasture), and a faecal egg
count in lambs of less than 1500 epg; clinical
parasitism was not observed. However, regular
anthelmintic drenching of lambs significantly
(P~0.01) increased liveweight gain of lambs from
weaning in November to May by an average 35%
over the 2 years. In year two, grazing ewes ahead
of lambs significantly increased (PcO.01) pasture
larvae levels and lamb faecal egg counts and
decreased liveweight gain compared with grazing
cattle ahead. Drenching ewes to minimise effects
of the post-parturient rise in faecal egg count had
no influence on nematode levels in lambs or on
lamb performance.
Keywords parasitic nematodes, grazing
management, lamb growth

Effects of reactive phosphate rock and superphosphate on sheep and pasture
production in hill countryS.F. LEDGARD and K.R. JONES

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Arad reactive phosphate rock (RPR) and single
superphosphate(SSP) were compared as phosphate
fertilisers in a sheep farmlet grazing trial and in two
mowing trials over 3 years. The trials were on a
volcanic ash soil at the MAF Te Kuiti Research
Area on a site with limited fertiliser addition in the
previous 2 years (Olsen P soil test averaged 10 in
the grazing trial). Soil sulphur levels were high and
there was no requirement for added sulphur over
the -3 years of the trial. Pasture and animal
measurements showed responses to SSP in all
years, with RPR being initially less effective than
SSP. By year 3, responses from RPR were near
those from SSP. Economicassessmentof thegrazing
trial corresponded with production data, except in
year 1 when there was little benefit from either
fertiliser. SSP was more cost-effective than RPR in
year2 whereas they were similarin year 3. Over the
3 years, both fertilisers were profitable and there
was an apparent cumulative net benefit from SSP
over RPR. It was estimated that by year 4 the
cumulative net benefit would be similar for both
fertilisers or would be reversed in favour of RPR.
Keywords reactive phosphate rock, hill country,
grazing trial, superphosphate, mowing trials

Evaluation of dryland species and new ryegrass cultivars to increase pasture
productivity in coastal TaranakiR.J. HAINSWORTH, N.A. THOMSON, D.A. McCALLUM and T.G. JUDD

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Seasonal and annual DM production of direct
drilled dryland species ‘Grasslands Maru’ phalaris
(Phalaris aquatica L.) and ‘Grasslands Roa’ tall
fescue (Festucuurundinuceu Schreb.) and perennial
ryegrass (Loliumperenne L.) cultivars ‘Grasslands
Pacific’, ‘Droughtmaster’ and ‘Yatsyn-1’ was
compared with that of established pasture in an
environment prone to summer dry spells. Two
methods of establishment using only Yatsyn-1
were examined: either the elimination of existing
pasture with glyphosate and drilling, or drilling
without spraying (undersowing).
Average annual DM production (over 3 years)
of Yatsyn-1 drilled into pasture previously sprayed
with glyphosate was 12% more productive than
established pasture. Maru phalaris, Droughtmaster
and Pacific had similar annual DM production to
established pasture, and Roa tall fescue produced
25% less. Yatsyn-1 undersown intopastures without
previous spraying with glyphosate produced 9%
less than Y atsyn- 1 established by the spray and drill
technique.
Phalaris established well but after 3 years the
content of phalaris had declined markedly,
suggesting poor persistency. Tall fescue was slow
establishing but had good persistency, as did all
ryegrass cultivars.
Yatsyn-1 direct drilled into pastures eliminated
with glyphosate before drilling is recommended for
an environment prone to summer dryness to increase
annual DM production.
Keywords pasture production,established pasture,
ryegrass cultivars, phalaris, tall fescue,
establishment techniques, summer droughts

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Four white clover (Trifolium repens L.) cultivars,
4 pre-release cultivars and 24 breeding lines were
evaluated in small plots in mixed species swards
under rotational cattle and sheep grazing for 2
years. There was no significant stock class x line
interaction for proportion of clover in the sward.
There was no evidence that medium- and smallleaved
types yielded better under sheep grazing
while larger-leaved types yielded better under cattle
grazing. Lines with the highest clover content
tended to be large leaved and upright irrespective
of stock class. They also had moderate to high
stolon growing point densities. Breeding programmes
have developed lines with high stolon
growing point densities, ensuring vegetative persistence,
while still maintaining a high proportion
of clover in the sward. These pre-release cultivars
and breeding lines gave significantly better clover
contents than existing cultivars.
Keywords cultivars, selections, plant habit,
cyanogenesis, stolon growing point density, clover
content, cattle grazing, sheep grazing

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The fungal endophyte Acremonium lolii, in
association with its ryegrass host, produces both
peramine, a feeding deterrent to Argentine stem
weevil,andlolitrem B,a neurotoxin causing ryegrass
staggers. Endophyte strains vary in the ratio of
production of these alkaloids in the ryegrass. In
field evaluations of several endophyte/ryegrass
- combinations, ‘Endosafe’, a zero lolitrem B, high peramine strain protected its host against Argentine
stem weevil attack and did not cause ryegrass
staggers in lambs grazing three of four ryegrass
cultivars. Lambs on the endophyte-free and
Endosafe combinations had the highest liveweight
gains and while endophyte-free ryegrass did not
cause ryegrass staggers it suffered significant stem
weevil damage. Ryegrasses with their ‘wild-type’
endophyte and a high lolitrem B strain ‘Waiau’,
had only minor stem weevil damage but caused
severe ryegrass staggers and weight loss in lambs.
Ryegrass with the no lolitrem B, low peramine
strain, ‘IOOA’, suffered some stem weevil damage
and although not causing ryegrass staggers, did
cause weight loss in lambs. Ryegrass/endophyte
metabolites in addition to lolitrem B may have
affected animal performance on endophyte-infected
ryegrass.
Keywords endophytc, Endosafe, perennial
ryegrass,ryegrass staggers, Argentine stem weevil,
liveweight gains, peramine, lolitrem B

Experiences with deferred grazing at the Taranaki Agricultural
Research StationD.A. McCALLUM, N.A. THOMSON and T.G. JUDD

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Deferred grazing is the practice of holding over
pasture in situ that has been considered surplus to
animal requirements in spring, to be grazed at a
later date when a shortage of pasture occurs, usually
in summer/autumn. This non-mechanical method
of pasture conservation was developedandpractised
from 1986-1989 at the Taranaki Agricultural
Research Station as part of a low cost dairy system.
At the low stocking rate (3.7 cows/ha) 13% of the
farm area was conserved as deferred grazing and
allowed to naturally reseed before grazing. The
reseeding doubled the tiller density of perennial
ryegrass, increasing pasture growth by 15 19% the
following season. This, combined with the nil cost
associated with conserving supplements, made this
system more profitable than the traditional haysilage
system.
For the natural reseeding to be successful, the
deferred grazed pasture should be removed from
thegrazingrotationduringtheryegrassreproductive
phase (mid-October to mid-November) and not
grazed until after the ryegrass seed is mature (mid-
January). The method developed to Wise deferred
grazed pasture has been to strip graze between the
morning and night milkings. Cows are offered a
pasture allowance of 10 kg DM/cow/day or one,
two hundred and fiftieth of the farm per day, to
achieve a utilisation of around 50%. Cows graze
selectively leavingaresidualofabout4000kg DM/
haofpredominantly dead material. Mowing before
grazing increased utilisation, but there was no
advantage in milk solids production. No benefits
were observed when tall fescue or phalaris pastures
were allowed to naturally reseed. Deferred grazing
had no effect on grass grub or porina populations if
grazed before April. No detrimental animal health
effects have been measured with deferred grazing.
To reduce farm operating costs and increase pasture
growth, it is recommended that 10% of the farm is
deferred and allowed to naturally reseed on an
annual basis.
Keywords deferred grazing, pasture conservation,
naturalreseeding, tiller density,pasture growth,
dairy production

Fertiliser history is a useful predictor of soil fertility statusD.G. MCCALL and B.S. THORROLD

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A Fertiliser index is described which consists of
summing total superphosphate applied to a site
after using an annual discount to past applications.
This index is related to relative pasture yield for 3
major New Zealand super-phosphate withholding
trials using a Mitscherlich function. A discount
factor of 0.15 was chosen. Accuracy of relative
pasture yield prediction was at least as good as for
an Olsen P predictor and better where sulphur
responses were implicated in the response to
super-phosphate (r-$0.77 to 0.93). The effect on
relative pasture yield predictions of measurement
errors in Olsen P and Fertiliser index were similar
using the Whatawhata site for comparison. A 20%
error in predictor resulted in a 3 unit error in relative
pasture yield estimation. Measurement errors in the
Fertiliser index are minimal if the last 10 years’
fertiliser history are known. Where this knowledge
is not available, 5 years of known fertiliser history
and use of national average fertiliser statistics
beyond that may give acceptable estimates of
relative yield. The advantage of the model for onfarm
use is that intended fertiliser use directly
affects the index and hence prediction of relative
pasture yield. This facilitates economic analysis of
options. An analysis using the model to investigate
production consequences of fertiliser use at the
industrylevelshowscontinuationofcurrentfertiliser
levels on hill country farms will result in a drop in
farm output of 13% in the next 10 years.
Keywords super-phosphate, discount, Olsen P,
policy, regional production, pasture yield, fertiliser
strategy

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Capital fertiliser dressings and intensified grazing
management (to fully utilise available pasture) are
shown to be essential components of hill country
pasture improvement options when they were
analysed by a computer simulation model. For
calculations to be profitable, animal performance
needed to exceed specified minima throughout the
period of development. For traditional mixed
livestock policies, these minima were that finishing
cattle reach 300 kg carcass weights and breeding
ewes achieve more than 100% lambing.
Keywords pasture improvement, gross margin,
reseeding

Group monitoring, a basis for decision making and
technology transfer on sheep and beef farmsR.W. WEBBY and G.W. SHEATH

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Group farm monitoring is a team approach to
technology transfer involving farmers, consultants
and researchers. Biological and financial
components of farm production are monitored to
provide data for decision making and a knowledge
of the farm which is shared among the
group.Scientists from the Whatawhata Research
Centre (WRC) provide comparative information
and relevant technology. Production gains on the
monitor farms have been achieved within 3 years
and further gains are possible. Group farmers benefit
from renewed enthusiasm in farming and an
increased interest in new technology. Key success
factors are group ownership of decisions and
outcomes and the credibility of consultants and
scientists who are seen to stand by the technology
delivered. MAF Technology consultants initiated
farm monitoring in the Northland area and have
benefited as have farmers through the WRC contact,
which provides a broad spectrum of information
from a multi-disciplined research group. Based on
the Northland success, group farm monitoring has
been accepted as a model for technology transfer
throughout New Zealand.
Keywords group farm monitoring, information,
decision making, technology transfer

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Three large glasshouse experiments were conducted
to identify white clover (Trifolium repens L.)
genotypes, and develop experimental seed lines,
with increased tolerance of low-phosphorus (P)
soils. The first compared the P response of 119
white clovercultivars; the second, the P response of
110 white clover genotypes from 11 selected
cultivars; and the third the P response of progeny
from crosses between genotypes selected for
differences in response to added P. There were
significant differences among cultivars and
genotypes for shoot dry weight response to added
P. Evaluation of progeny showed that high P
response was dominant over low P response, the
general combining abilities of all high P response
genotypes were greater than that of the low P
response genotypes, and that narrow sense
heritabilities for P response were moderate (~0.4).
The chances of manipulating differences in P
response by breeding, application of the results to
dateandfuturedirectionsofthisworkarediscussed.
Keywords white clover, Trifolium repens,
phosphorus response, low-phosphorus tolerance,
heritability, breeding, combining ability

Introduction of chicory to a Bay of Plenty sheep farmROBERT LJNTON, KEVJN MCKINLEY and MARK LINTON

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Low ewe liveweights and general performance on
Bay of Plenty sheep farms is a common problem
aggravated by farmers keeping lambs through late
autumn in an attempt to improve returns. Ewe
liveweights of 50 kg or less result in low lambing
percentages and wool production of around 4.4 kg/
sheep stock unit.
This paper outlines one farmer’s identification
of the problem and the introduction of ‘Grasslands
Puna’ chicory to help solve this problem. A pure
sward was very well established using the spraydrill
technique at relatively low cost, despite a late
sowing date. Several options now present themselves
to increase profitability and flexibility on the
property.
Keywords chicory, lamb growth, Bay of Plenty

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A prototype strip seeder was developed to establish
grasses and legumes in the semi-arid and montane
environments of the Mackenzie Basin and Central
Otago. Specifications of the strip-seeder required
for cost-effective performance were identified on
the basis of previous direct drilling investigations
in this environment, and included: (a) removal of a
strip of existing vegetation to reduce competition;
(b) creation of seed bed tilth; (c) controlled and
separate placement of seed and fertiliser; and (d)
compaction of the drilled seed bed to enhance
contact between seed and soil. The prototype strip
seeder was built around a modified Duncan 730
multi-seeder chassis, and was used to install spring
and autumn trials at Eamscleugh in Central Otago
and at Ohau Downs in the Mackenzie Basin.
Mechanical improvements were made as the trials
progressed. The experience gained, and results
from the trials, confirm the suitability of the
prototype strip seeder concept for successfully
introducing grasses and legumes into this terrain.
Keywords direct drilling, strip seeder, seed
placement, seed depth, sowing depth

Maori land utilisationALISTAIR M. HALL

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The Maori land resource in the Bay of Plenty
district is variously defined as to area and undefined
as to land use. A general resumé of Maoti land title
and tenure is given and procedures on succession
commented on. Two statutory avenues which may
assist utilisation, the establishment of trusts under
section 438 of the Maori Affairs Act, and the
establishment of Maori Incorporations, are
discussed. Lending for development on the security
of Maori land was largely the preserve of the now
defunct Maori Affairs Department. No commercial
organisation has emerged to undertake this role and
development of Maori land on any appreciable
scale is now likely to cease.
Keywords Maori land, legislation, succession,
utilisation, mortgages.

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The effects of applying nitrogen (N) fertiliser at
100 kgN/ha as a split application (40 kgN/ha in
July/ early August and 60 kgN/ha in October) and
of earlier calving (16 July vs 2 August) on milk
solids production and farm profitability were evaluated
at the Waimate West Demonstration Farm in
South Taranaki. Two systems were comparedover
3 years: calving on 2 August with no N (LC) and
calving on 16 July with N (ECN). In the second and
third year calving on 16 July with no N (EC) was
also evaluated. All herds were stocked at 4.0 cows/
ha. Early calving without N (EC) increased the
average lactation length/cow by only 2 days because
poorer cow condition andless winter supplements
required earlier drying off. Milkfat increased
by only 13 kg/ha and protein by 1 kg/ha.
Early calving with N (ECN) increased the
average lactation length/cow by 16 days, milkfat
by 57 kg/ha and protein by 27 kg/ha. Nitrogen
applied in October was more effective (kg milk
solids/kg N) at increasing milk solids production
(1.08 kg milk solids/kg N) than N applied in late
winter (0.56kg milk solids/kg N). At 4.0 cows/ha
and calving on 16 July, the break-even milkfat
price for N use was $3.OO/kg fat.
Keywords milk solids, production, nitrogen
fertiliser, calving date.

Natural reseeding of five grass species in summer dry
hill countryD.E. HUME and D.J. BARKER

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Natural reseeding of 5 grass species was monitored
over 2-3 years in summer dry hill country in
central Wairarapa and Taupo. Measurements
included numbers of seedheads and seedlings
appearing, survival andgrowth of tagged seedlings
and their contribution to sward tiller populations.
Effects of fertiliser (high, low) and summer grazing
managements (continuously summer grazed,
spelled from grazing during summer) were
examined.
All seedlings appeared in autumn/early winter.
No seedlings of phalaris and few tall fescue
and cocksfoot seedlings were found, and all failed
to survive the first summer. Reseeding of prairie
grass was significant, failure of which corresponded
with a general decline in persistence of
prairie grass swards. With summer spelling in
central Wairarapa, prairie grass had relatively
high seedling numbers (144/m?), seedling survival
(10%) and contribution (11%) to prairie
grass tillers in the sward. Reseeding was most
prolific for perennial ryegrass (Nui and resident
ryegrass) (283 seedlings appeared/m2). Summer
spelling gave high ryegrass seedling numbers in
central Wairarapa but lower numbers at Taupo,
compared with summer grazing. At both sites,
however, summer grazing increasedryegrass seedling
survival and seedling contribution to the total
sward (11% of total tillers), despite inherently
dense, competitive swards. Effects of fertiliser
were generally minor. Variation between sites and
years was considerable. Reseeding had little effect
on numbers of new plants in the sward, but
may be significant when considered cumulativley
over a number of years.
Keywords natural reseeding, summer dry hill
country, summer grazing managements, fertiliser,
prairie grass, ryegrass, phalaris, cocksfoot, tall
fescue

Nitrogen fertiliser use in early lambing systemsG.W. SHEATH, C.J. BOOM and R.W. WEBBY

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Nitrogen fertiliser was applied in June 1990 to
early-August lambing systems and production was
compared with traditional September lambing.
Nitrogen (30 kg N/ha) increased pasture growth
rates by 3-4 kg DM/ha/day and increased production
by 210 kg DM/ha during July-September
inclusive, Nitrogen responses were greatest in southfacing
paddocks; least on easy contoured paddocks;
and did not differ between “resident” pastures
and “improved” pastures that had been
oversown with new pasture cultivars 5 years before.
Compared with traditional September lambing,
early-August lambing (plus N) resulted in20%
fewer lambs at weaning; 2.4 kg heavier lamb
weaning weights; similar ewe weaning weights;
and similar bull live weights in January. While N
applications to earlier lambing systems reduced the
differences in ewe and bull weights previously
recorded between the lambing date treatments, it
was not a profitable strategy. Assessment of pasture
response to N (30 kg N/ha) was repeated in 1991.
Nitrogen increased production by 260 kg DM/ha
and responses were similar for all paddock and
pasture types.
Keywords nitrogen fertiliser, early lambing, hill
country

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The effect of a pastoral fallow (the ‘spelling’ of a
pasture from early spring (September) to autumn
(April/May)), with or without added fertiliser, on
pasture and legume growth rates, total pasture
biomass accumulation, nitrogen fixation, and on
soil carbon and nitrogen cycling in the year of the
fallow, and in the year after thef allow, wa sevaluated
on 55ha of moderate to steep~low fertility, summermoist
hill country at Ballantrae, DSIR Grasslands
Hill Country Research Station.
The major effect was to open the sward, increase
individual plant size, vigour and rooting depth,
increase the presence and vigour of white clover
by creating new niches for growth, and improve N
fixation by legumes in the year after the fallow
only. The data on soil C and N dynamics are
consistent with the concept of fallowing adding a
pool of potentially available N to the soil. The
benefits of a fallow for moist hill country and other
pastoral farming systems are discussed.
Keywords pastoral fallow, hill pastures, nitrogen,
legume growth

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Ryegrass monocultures and mixtures containing at
least one or two other grass species were compared
on three sites over 3-6 years. At Atiamuri, under
intensive dairying, a tall fescue-cocksfoot pasture
yielded 3.7 t/ha/yr, and 14 kg/ha/day in spring and
17 kg in summer, more than the mdnocuiture.
Under dairying at Opiki, a phalaris-ryegrass
mixture yielded 1.8 t/ha/yr, and 5 kg/ha/day in
winter and 7 kg in autumn, more than the
monoculture.
At Castlepoint Station, a cocksfoot-tall fescue
pasture yielded 1.4 t/ha/yr, and 11 kg/ha/day in
summer, more than the monoculture. These pastures would more closely meet (or exceed) animal feed
demands, so increasing gross farm income through
increased animal performance and carrying
capacity.
Keywords Grasslands Kara cocksfoot,
Grasslands Maru phalaris, Grasslands Puna chicory,
Grasslands Roa tall fescue, ryegrass monoculture,
dry matter yield, animal demand

Priorities for development on a wet coastal Bay of Plenty
conversion propertyP. LIVINGSTGN and R. KYLE

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Dairy conversion units are as individual as the
persons operating them. The need for flexibility in
planning is easily demonstrable. Less than 6 months
after purchasing a second-year conversion property
near Edgecumbe the owners discovered a need to
review fully the goals and objectives encompassed
in their management plan. Such a move had been
“forced” upon them for several reasons, primarily:
(i) an announcement that milk solid (fat and protein)
returns could be up to 25-30% lower than
initially anticipated and
(ii) the prompt recognition that pasture performance
reflected much greater variation than earlier
thought.
Short- and medium-term goals were reviewed,
resulting ina shift in priority from pasture renovation
and increased stocking rate to additional drainage
and fertiliser. The confidence to make such changes
was provided through a decision-making process
classed as “whole-farm technology transfer”.
Decisions that affect one component of the dairy
production system are not made in isolation from
the effects on another. Decision-making on this
property is a stepwise, consultative process based
on objective rather than subjective means and
focuses on the ‘wider vision’ of the property owners.
Keywords decision-making. goals and objectives,
dairy conversion, whole farm technology transfer,
management support

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A 5-year experiment at Ruakura Agricultural Centre measured the effects of blanket application of
glyphosate herbicideand direct drilling ofperennial
ryegrass and white clover on seasonal pasture
composition and production. Plots were sprayed in
autumn 1985 with 6,4,2 and 0 l/ha of glyphosate
before direct drilling with a mixture of ‘Ellett’
ryegrass and ‘Grasslands Kopu’ white clover. These
treatments werecompared with plots of the original
paspalum pasture which was not sprayed or drilled.
Plots were arranged at random in 6 replicate blocks
that were rotationally grazed by dairy cows.
Applying high rates (4-6 l/ha) of glyphosate
completely eliminated paspalum from the pasture
and subsequently, treatment differences between
the 6 and 4 l/ha treatments for most variables were
small. Differences in winter/spring herbage
accumulation between the 4 l/ha treatment and the
control plots were highest in the first year and
declined with time, representing 1.9,0.8,0.8.0.6
and 0.4 t DM/ha, respectively, over the S years of
the trial. The declining growth response was
paralleled by an increasing level of paspalum in the
previously sprayed plots, which exceeded 30% of
DM by the fourth summer. Over the same period,
their summer ryegrass contents had declined by
more than half (46-20% of DM). These results
suggest that for this site further renovation using
glyphosate (at 4 l/ha) would be beneficial after 4
years to recapture the immediate superior growth
responses, and since the costs of renovation could
be met within 2 years.
Keywords Paspalum dilitatum, Lolium perenne,
seasonal herbage accumulation, renovation
methods, glyphosate herbicide, dairy pastures,
volunteer paspalum invasion, pasture botanical
composition stability

Resident ryegrass in hill country pasturesM.E. WEDDERFSURN and W.J. PENGELLY

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The attributes of 1800 ryegrass plants removed
from North Island hill country aredescribed and the
implications for oversowing discussed. Morphology
was varied but the mean of the population was
prostrate and densely tillered, resulting in dense
pastures under intensive grazing. Although morphology
was not related to the site of plant origin,
agronomic response to low nitrogen and moisture
stress was. Plants from north-facing steep areas
responded least to application of nitrogen or water
indicating a low relative growth rate. A probable
survival mechanism for moisture-stressed plants is
reduced vegetative growth and increased seed set.
Response to moisture stress was found to be heritable.
In moderate-high fertility steep sites total
ryegrass production has not increased after
oversowing new cultivars. It is assumed that this is
a reflection of the number of niches available for
ryegrass exploitation. Our studies show that the
strength of existing ryegrass is its genetic diversity
and its ability to exploit the various niches present
in hill country. The growth and expansion of these
ryegfass populations should be actively encouraged.
In niches below the optimum for rycgrass
growth new species should be introduced.
Keywords hill country, perennial ryegrass,
morphology, stress, genetics, oversowing,
management

Seasonal patterns of pasture production in the Bay of Plenty
and WaikatoJ.A. BAARS, G.J. GOOLD, M.F. HAWKE, P.J. KILGARRIFF and M.D. ROLM

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Patterns of pasture growth were measured on 3
farms in the Bay of Plenty (BOP) and at No2 Dairy
(Ruakura Agricultural Centre) in the Waikato from
1989 to 199 1. A standardised trim technique with
cages and 4-weekly cutting under grazing was
used. Long-term seasonal growth patterns, using a
predictive pasture model, were also simulated.
Simulated pasture growth from long-term climatic
data shows that pasture growth rates are higher in
winter, early spring and late autumn in the BOP
than the Waikato. However, the actual measurements
over the 2 years show that pasture growth
over the latter periods is lower at the BOP sites than
at the Waikato site. In the BOP the spring peak is
much later than in the Waikato while an early
summer peak, with higher growth rates than in the
Waikato, occurred in the BOP. No such summer
peak was evident in the Waikato. The difference
between the two regions is caused by the large
contribution of subtropical grasses to sward production
in summer and autumn, The prolific summer
growth of subtropical grasses may explain the
low ryegrass content and low pasture production in
winter. The lower than expected autumn, winter,
spring production may also becaused by low clover
content, possibly a result of competition from
subtropical grasses and a sulphur deficiency. The
apparent low amount of nitrogen fixed by clover
may explain the low rates of pasture production
over the cooler season. Applications of nitrogen
fertiliser may substantially increase dry matter
production from April to September.
Keywords pasture,simulation,subtropical grasses,
Paspalum, Digitaria sanguinalis, growth rates

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The process of setting targets and intensively
monitoring performance on an Opotiki dairy farm
improved milkfat production over one season by
6% when compared to surrounding farms. By
comparing actual results with performance targets
a number of constraints to improved milk production
were identified. The constraint given highest priorty
was the extended calving spread. Management was
implemented to overcome this constraint with the
result of a mean calving date 19 days earlier. This
improvement was the major reason for the 6%
production increase.
Keywords: Comparative Farm Programme, targets,
monitoring, constraints, pasture growth, utilised
pasture

Soil nutrient status of the Bay of Plenty region and the implications to pasture
productivity and fertiliser requirementsS.F. LEDGARD, T.J.M. JOHNSTON, D.C. EDMEADES and D.M. WHEELER

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The soil nutrient status of sheep and beef, and dairy
farms in the Bay of Plenty region was examined
using results from over 4700 soil samples analysed
by MAF between 1988 and 1991. The proportion of
farms in various soil test categories was determined
and related (using known relationships) to the
potential responsiveness of pastures to fertiliser
nutrient additions. About 70% of farms had soil
phosphorus (P) tests below optimum values,
indicating that pasture production would be
increased by addition of P fertiliser on these farms.
Similarly,about 50% of farms hadbelow-optimum
levels of sulphur (S) and potassium (K). Pasture
production on most farms was limited by more than
one nutrient and a relatively high proportion of
pumice soils had low levels of P, S and K. Pumice
soils are prone to large leaching losses of added
sulphate S and field experimental results indicated
that elemental S (in sulphur superphosphate) was
more efficient at increasing pasture production on
these soils than sulphate S (in superphosphate). Soil
test data was also used to indicate that about onethird
of sheep and beef, andone-half of dairy farms
were suitable for use of slow-release reactive
phosphate rock (RPR) as a source of P, as indicated
by soil pH56.0 and MAF fertiliser P requirements
at or above maintenance levels.
Keywords soil test, fertiliser requirement,
phosphorus, sulphur, potassium, slow-release
fertiliser

Some basic concepts of pasture seed mixtures for New Zealand farmsJ.F.L. CHARLTON

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Seeds mixtures for New Zealand pastures developed
from British practices with sowing of multi-species
seeds mixtures during early years of settlement.
Breeding and seed production of ryegrasses and
clovers in the 1930s led to use of simple mixtures,
still the most commonly used. Since the mid 197Os,
new species have been released, and are now
becoming more popular. Advantages and some
potential problems of species mixtures are outlined,
and simple concepts of compiling seeds mixtures
are explained, with particular reference to seeding
rate and sowing time.
Keywords species, seeds mixtures, pasture
renewal, sowing rates, seedling establishment,
competition

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A computer program called Stockpol is described.
It is a biological model designed for decision support
applications on pastoral farms. Individual
farm scenarios are defined in terms of component
subfiles which define stock (numbers and
performance), land (area, pasture growth rates and
land use), prices and constants. Physical and
financial reports are available for individual
scenarios, and for comparisons among scenarios.
Once defined, scenarios are tested for biological
feasibility by calculating if there is enough pasture
cover on the farm at all times to meet animal
requirements for targetperformance levels. Policies
for biologically unfeasible farms can be
automatically modified if necessary. Stockpol can
be used to analyse long-term policy changes or
short-term feed budgets, but it is not suitabIe for
paddock-level feed budgeting.
Keywords sheep, beef, pasture growth, pasture
cover, feed budget, biological feasibility, prices,
profits, computer model

The beef breeding herd: options for using winter feed most productivelyW.H. McMILLAN and D.G. MCCALL

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A spreadsheet model has been developed to allow
a comparison of policies for beef breeding cows.
The criterion for comparison is the kg of calf
weaned per kg of winterfeed required i.e. efficiency. The model allows adjustment in number of animals
wintered so that all policies have the same winter
feed requirement. Policies which favour higher
efficiencies include: timing mean calving date at
the end of the winter, using breeds of bull with high
growth rate and high survival rate progeny, older
rather than younger herd age structures. and
wintering only pregnant heifers and cows after
pregnancy diagnosis. The most scope for improving
efficiency is in herd age structure while the least
scope is in calving date. The analysis demonstrates
that that the most efficient options are a combination
of policies. The best combination is about 26%
more efficient than the worst combination. National
beef herd statistics are required to assess the likely
impact of changes on the industry.
Keywords: beef cows, weaning weight, herd age
structure, pregnancy diagnosis, feed requirements, time of calving, terminal sires

The pasture ryegrass plant, what is it?J.L. BROCK and V.J. THOMAS

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Detailed studies of plant growth processes are
important in understanding the performance and
persistence of species in pastures, particularly in
response to uncharacteristic environmental stress.
The morphology of perennial ryegrass plants in
mixed sheep grazed pastures was determined in self
contained farmlets undercontrasting managements
of rotational grazing, set stocking or a combination
of both. Average size was 90 mg total DW, with 4-
5 tillers and 12-13 leaves, little different to white
clover. Ryegrass exhibits strong clonal growth,
with extension at the apex and death of the basal
stem releasing branches to form new plants at
regular intervals, maintaining a stable population
structure of small plants all year. The normally
short internodes on ryegrass stems can elongate to
form stolon and elevate the apex to a more favourable
position if survival is threatened. On average only
2530% of plants contained stolon at any one time.
Because of high plant density the quantities of
ryegrass stem present was often in excess of that
produced by white clover in the same swards.
Grazing management did not affect plant structure
(numbers of tillers, leaves etc) only their size (dry
weight), but had marked effects on pasture structure
and subsequent survival of plants under stress.
Keywords perennial ryegrass, plant morphology,
grazing management, seasonal variation, plant
survival, stolon formation

The productivity of Maku Lotus as a forest understoreyG.G. WEST, M.G. DEAN and N.S. PERCIVAL

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Oversowing Lotus uliginosus cv. ‘Grasslands
Maku’ offers considerable scope for improvement
of understorey forage production in New Zealand’s
plantation forests. In a grazing trial in
Kaingaroa Forest annual forage yields of predominantly
Maku lotus were 3000-5000 kg/ha dry
matter (DM) from tree age 4-7 years but declined
to 1000-3000 kg DM/ha by age 11 years. Forage
yields available for grazing under different tree
stockings (100,200 and400 stems/ha) were (up to
treeage 11) approximately the same, in spiteof the
percentage area covered with slash being significantly
affected by tree stocking. Forage species
composition since time of oversowing has changed
from initial stands of almost pure lotus to a mixture
of lotus and lower fertility grasses, particularly
Yorkshire fog, and flat weeds. By tree age 11
years (8 years after oversowing) lotus comprises
20-30% of understorey ground cover, both with
and without cattle grazing.
Keywords Maku lotus, forest understorey, forest
grazing, oversowing, forage yields

The role of beef breeding cows in strategic management of feed supply under
pasture variabilityA.B. PLEASANTS, R.A. BARTON and P.J. BATLEY

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The ability of the beef cow to buffer herself against
pasture variability by losing liveweight at certain
periods in the production cycle is reviewed. The
point is made that this attribute of the beef cow can
be used to buffer other enterprises on the farm less
able to cope with variability in pasture feed supply.
It is suggested that a farm livestock policy should
include livestock classes like the beef cow which,
because of their ability to buffer against variability
in pasture feed supply,canresultinamoreefficient,
and more economic use of pasture on the farm.
Keywords Beef cow, nutrition, pasture variability,
flexibility, buffering capacity, risk management

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This paper describes the research method adopted
to identify the constraints to biological (chemical-free)
sheep and beef production and to develop
management systems that overcome these
constraints. The method adopted to meet these
objectives has three distinct phases; I A farmlet
study, II Component research, and III Farmer
survey and on farm testing.
The objective of the farmlet study was to
establish two farmlets, initially as similar as
possible in terms of stock numbers and
management practices. The only constraint
imposed on the biological and not the conventional
farmlet, is that the management practices must
comply with the production standards of the
New Zealand Biological Producers Council. The
conventional farmlet acts as a baseline against
which the performance of the biological farmlet
can be compared, and to identify constraints to
biological hill country sheep and beef production.
Component research is used to investigate
alternative methods of overcoming these
constraints. The third phase of the programme is
to survey practising biological producers, which
number 50 at present, to identify their major
constraints to production and to describe the
management practices of successful biological
producers. The information from this survey could
then be used to further develop the biological
farmlet and component research programme.
Progress to date in the farmlet study and the
information system used to manage and evaluate
the performanceof the conventional and biological
farmlet is also detailed.
Keywords: biological, chemical-free, alternative
farming, hill country, research method

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Pastures in the northern North Island contain a
complex of nationally distributed insects and insects
associated with warmer climatic conditions.
Argentine stem weevil (Listronotus bonariensis
(Kuschel)) is the most important insect pest in New
Zealand. Progress toward the development of
sustainable control of Argentine stem weevil is
basedon a thorough understanding of the population
ecology of the pest.The population size of Argentine
stem weevil depends on the number of Acremonium lolii-free ryegrass tillers in the sward. Identification
of A. lolii-free ryegrasses that are tolerant/resistant
to Argentine stem weevil may improve ryegrass
production and persistence without endangering
animal health. The release of a South American
parasite and the utilisation of naturally occurring
pathogenic fungi together with tolerant/resistant
ryegrasses has the potential to provide long term
sustainable control of Argentine stem weevil in pastures .
Keywords: endophyte, plant resistance,pathogens,
biological control

Utilisation of wastes as fertilisers with particular emphasis on the Bay of
Plenty regionM.B. O’CONNOR, A.H.C. ROBERTS, R.D. LONGHURST and M.F. HAWKE

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Estimates of the wastes produced in the Bay of
Plenty region indicate that 22 million m’ (tonnes)
is produced annually. The main contributors to
waste production are the dairy industry (shed,
factory),municipal sewage, pig, poultry, meatworks,
kiwifruit, fishing and pulp and paper industries. In
fertiliser terms these wastes are valued at $7.7
million. In addition the timber industry produces >
1 million tonnes of timber residues (sawdust, bark,
woodchips) approximately 20% of which is
currently dumped. Wastes, when recycled back on
to the land, offer a potential source of nutrients to
enhance pasture and crop production. In addition
organic wastes provide a source of organic matter
which may have beneficial effects on the physical
properties of soils.
Research results indicate that pumice soils are
well suited to the application of wastes. Some
general recommendations are given for the use of
wastes in dairying, orcharding and cropping
situations. Three factors are considered important
for the successful utilisation of wastes (a)
application rates need to be balanced to the nutrient
needs of the soil-plant system (b) safeguards in the
form of regular chemical monitoring of the effluent,
soil, plant and animal need to be implemented,
and(c) the economics of using the waste materials
must be favourable to the farmer and orchardist.
The principle of the producer of the waste paying
for its safe disposal or utilisation needs to be
adopted in New Zealand as it has in many overseas
countries.
Keywords nutrients, organic matter, waste
recycling, pumice soils, fertiliser value